THE FINAL FRONTIER - SAFETY BY DESIGN: EMERGING STANDARDS AND DESIGNS IN LOW-VOLTAGE MOTOR CONTROL ASSEMBLIES

摘要

Over the past several years a growing focus on improved electrical safety has arisen. A better understanding of both electrical shock and arc flash hazards faced by personnel working on or near energized equipment has led to consensus standards such as the NFPA-70E. These standards deal primarily with safe work practices - designed to identify and quantify the hazard, then assure that personnel are clothed with appropriate personal protective equipment (PPE) to reduce the risk. Consensus opinion among safety experts is that the best method to reduce the risk of injury is by designing the hazards out. The next frontier in reducing electrical injuries will arise from improved designs of electrical products which mitigate hazards by design. One primary product area of interest is the low-voltage motor control center used for control of motors rated 1000 volts and below. In process applications such as cement, pulp & paper and petroleum & chemical plants, maintenance personnel often find it necessary to work on, or near, energized motor control centers while performing maintenance and operational activities. This paper will review work in progress by the Institute of Electrical and Electronics Engineers (IEEE) Working Group 1683 "Standard for Motor Control Centers Rated up to 1000 volts with Requirements Intended to Reduce Injuries" Working Group. This group was initially formed by the IEEE Industry Applications Society Petroleum & Chemical Industry Committee and is working on ideas to improve the functional design and test requirements for motor control centers rated up to 1000 volts ac 50/60 Hz with specified safety and reliability features. The paper will briefly review the emerging standard and advise engineers that are interested in how to get involved to offer inputs for improving the standard. Information on new safety based low-voltage motor control center designs that have been recently introduced by several manufacturers will be reviewed. The review will show how the industry is responding to the product need articulated by the user community and the IEEE 1683 Working Group for product safety by design.